/*
 * Copyright (C) 2007 Google Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.google.common.collect;

import java.util.Collection;
import java.util.Comparator;
import java.util.Map;
import java.util.Set;
import java.util.SortedSet;

import javax.annotation.Nullable;

import com.google.common.annotations.GwtCompatible;

/**
 * A {@code SetMultimap} whose set of values for a given key are kept sorted;
 * that is, they comprise a {@link SortedSet}. It cannot hold duplicate
 * key-value pairs; adding a key-value pair that's already in the multimap has
 * no effect. This interface does not specify the ordering of the multimap's
 * keys.
 * 
 * <p>
 * The {@link #get}, {@link #removeAll}, and {@link #replaceValues} methods each
 * return a {@link SortedSet} of values, while {@link Multimap#entries()}
 * returns a {@link Set} of map entries. Though the method signature doesn't say
 * so explicitly, the map returned by {@link #asMap} has {@code SortedSet}
 * values.
 * 
 * @author Jared Levy
 * @since 2010.01.04 <b>stable</b> (imported from Google Collections Library)
 */
@GwtCompatible
public interface SortedSetMultimap<K, V> extends SetMultimap<K, V> {
    /**
     * Returns a collection view of all values associated with a key. If no
     * mappings in the multimap have the provided key, an empty collection is
     * returned.
     * 
     * <p>
     * Changes to the returned collection will update the underlying multimap,
     * and vice versa.
     * 
     * <p>
     * Because a {@code SortedSetMultimap} has unique sorted values for a given
     * key, this method returns a {@link SortedSet}, instead of the
     * {@link java.util.Collection} specified in the {@link Multimap} interface.
     */
    SortedSet<V> get(@Nullable K key);

    /**
     * Removes all values associated with a given key.
     * 
     * <p>
     * Because a {@code SortedSetMultimap} has unique sorted values for a given
     * key, this method returns a {@link SortedSet}, instead of the
     * {@link java.util.Collection} specified in the {@link Multimap} interface.
     */
    SortedSet<V> removeAll(@Nullable Object key);

    /**
     * Stores a collection of values with the same key, replacing any existing
     * values for that key.
     * 
     * <p>
     * Because a {@code SortedSetMultimap} has unique sorted values for a given
     * key, this method returns a {@link SortedSet}, instead of the
     * {@link java.util.Collection} specified in the {@link Multimap} interface.
     * 
     * <p>
     * Any duplicates in {@code values} will be stored in the multimap once.
     */
    SortedSet<V> replaceValues(K key, Iterable<? extends V> values);

    /**
     * Returns a map view that associates each key with the corresponding values
     * in the multimap. Changes to the returned map, such as element removal,
     * will update the underlying multimap. The map never supports
     * {@code setValue()} on the map entries, {@code put}, or {@code putAll}.
     * 
     * <p>
     * The collections returned by {@code asMap().get(Object)} have the same
     * behavior as those returned by {@link #get}.
     * 
     * <p>
     * Though the method signature doesn't say so explicitly, the returned map
     * has {@link SortedSet} values.
     */
    Map<K, Collection<V>> asMap();

    /**
     * Returns the comparator that orders the multimap values, with a
     * {@code null} indicating that natural ordering is used.
     */
    Comparator<? super V> valueComparator();
}
